diff --git a/src/third_party/wiredtiger/src/conn/conn_log.c b/src/third_party/wiredtiger/src/conn/conn_log.c
index 3521359..7113a0f 100644
--- a/src/third_party/wiredtiger/src/conn/conn_log.c
+++ b/src/third_party/wiredtiger/src/conn/conn_log.c
@@ -377,16 +377,17 @@ __wt_log_wrlsn(WT_SESSION_IMPL *session, WT_CONNECTION_IMPL *conn, WT_LOG* log,
 	WT_LOG_WRLSN_ENTRY written[SLOT_POOL];
 	WT_LOGSLOT *slot;
 	size_t written_i;
-	uint32_t i, save_i;
+	uint32_t i, save_i, max_i;
 
 	i = 0;
 	written_i = 0;
         *free_slot = NULL;
+	max_i = WT_MIN(log->max_used+1, SLOT_POOL-1);
 	/*
 	 * Walk the array once saving any slots that are in the
 	 * WT_LOG_SLOT_WRITTEN state.
 	 */
-	while (i < SLOT_POOL) {
+	while (i <= max_i) {
 		save_i = i;
 		slot = &log->slot_pool[i++];
 		if (!*free_slot && slot->slot_state==WT_LOG_SLOT_FREE)
@@ -470,6 +471,12 @@ __wt_log_wrlsn(WT_SESSION_IMPL *session, WT_CONNECTION_IMPL *conn, WT_LOG* log,
 
 	}
 
+	// adjust log->max_used
+	while (log->slot_pool[max_i].slot_state==WT_LOG_SLOT_FREE && max_i>0)
+		--max_i;
+	if (*free_slot)
+		max_i = WT_MAX(*free_slot - log->slot_pool, max_i);
+	log->max_used = max_i;
 	return 0;
 }
 
diff --git a/src/third_party/wiredtiger/src/include/log.h b/src/third_party/wiredtiger/src/include/log.h
index 66f346e..90a7c9e 100644
--- a/src/third_party/wiredtiger/src/include/log.h
+++ b/src/third_party/wiredtiger/src/include/log.h
@@ -158,6 +158,7 @@ typedef struct {
 #define	SLOT_ACTIVE	1
 #define	SLOT_POOL	128
 	uint32_t	 pool_index;		/* Global pool index */
+	uint32_t	 max_used;		/* largest non-free slot */
 	WT_LOGSLOT	*slot_array[SLOT_ACTIVE];	/* Active slots */
 	WT_LOGSLOT	 slot_pool[SLOT_POOL];	/* Pool of all slots */